这应该可以通过percent_rank()实现

select score
from (
  select score, percent_rank() over (order by score desc) as pct_rank
  from scores
) t
where pct_rank <= 0.99

可以使用ntile函数将行划分为百分点，然后选择tile〉99的行
例如：

-- following query generates 1000 rows with random 
-- scores and selects the 99th percentile using the ntile function.
-- because the chance of the same random value appearing twice is extremely
-- small, the result should in most cases yield 10 rows.
with scores as (
  select
    id
  , random() score
  from generate_series(1, 1000) id
 )
, percentiles AS (
  select 
    *
  , ntile(100) over (order by score) tile
  from scores
)
select 
  id
, score
from percentiles 
where tile > 99